diff options
Diffstat (limited to 'generator/pamcrater.c')
| -rw-r--r-- | generator/pamcrater.c | 192 |
1 files changed, 139 insertions, 53 deletions
diff --git a/generator/pamcrater.c b/generator/pamcrater.c index d61ce548..50745501 100644 --- a/generator/pamcrater.c +++ b/generator/pamcrater.c @@ -62,8 +62,10 @@ struct CmdlineInfo { unsigned int width; unsigned int randomseedSpec; unsigned int randomseed; + unsigned int verbose; unsigned int test; unsigned int radius; + int offset; }; @@ -81,7 +83,7 @@ parseCommandLine(int argc, const char ** const argv, optStruct3 opt; unsigned int option_def_index; - unsigned int numberSpec, heightSpec, widthSpec, radiusSpec; + unsigned int numberSpec, heightSpec, widthSpec, radiusSpec, offsetSpec; MALLOCARRAY_NOFAIL(option_def, 100); @@ -94,10 +96,14 @@ parseCommandLine(int argc, const char ** const argv, &widthSpec, 0); OPTENT3(0, "randomseed", OPT_UINT, &cmdlineP->randomseed, &cmdlineP->randomseedSpec, 0); + OPTENT3(0, "verbose", OPT_FLAG, NULL, + &cmdlineP->verbose, 0); OPTENT3(0, "test", OPT_FLAG, NULL, &cmdlineP->test, 0); OPTENT3(0, "radius", OPT_UINT, &cmdlineP->radius, &radiusSpec, 0); + OPTENT3(0, "offset", OPT_INT, &cmdlineP->offset, + &offsetSpec, 0); opt.opt_table = option_def; opt.short_allowed = FALSE; /* We have no short (old-fashioned) options */ @@ -122,6 +128,9 @@ parseCommandLine(int argc, const char ** const argv, if (cmdlineP->width == 0) pm_error("-width must be positive"); + if (!offsetSpec) + cmdlineP->offset=0; + if (cmdlineP->test) { if (!radiusSpec) pm_error("With -test, you must specify -radius"); @@ -139,6 +148,9 @@ parseCommandLine(int argc, const char ** const argv, if (radiusSpec) pm_error("-radius is meaningful only with -test"); + if (offsetSpec) + pm_error("-offset is meaningful only with -test"); + if (!numberSpec) cmdlineP->number = 50000; @@ -149,9 +161,6 @@ parseCommandLine(int argc, const char ** const argv, } -/* Definitions for obtaining random numbers. */ - -/* Display parameters */ static double const arand = 32767.0; /* Random number parameters */ static double const CdepthPower = 1.5; /* Crater depth power factor */ @@ -161,7 +170,9 @@ static double const DepthBias2 = 0.5; /* Square of depth bias */ static double const cast(double const high) { - +/*---------------------------------------------------------------------------- + A random number in the range [0, 'high']. +-----------------------------------------------------------------------------*/ return high * ((rand() & 0x7FFF) / arand); } @@ -196,8 +207,15 @@ terrainModP(struct pam * const pamP, tuple ** const terrain, int const x, int const y) { +/*---------------------------------------------------------------------------- + A pointer to the sample in 'terrain' of an image described by *pamP that is + at Column 'x' of Row 'y', but modulus the image size. - return &terrain[mod(y, pamP->height)][mod(x, pamP->width)][0]; + So e.g. if the image is 10 x 10 and 'x' and 'y' are both 12, our value + would be a pointer to the sample at Column 2 or Row 2. If they are both + -1, we would point to Column 9, Row 9. +-----------------------------------------------------------------------------*/ + return &terrain[mod(x, pamP->height)][mod(y, pamP->width)][0]; } @@ -208,25 +226,49 @@ terrainMod(struct pam * const pamP, tuple ** const terrain, int const x, int const y) { +/*---------------------------------------------------------------------------- + The value of the sample in 'terrain' of an image described by *pamP that is + at Column 'x' of Row 'y', but modulus the image size. + So e.g. if the image is 10 x 10 and 'x' and 'y' are both 12, our value + would be the value of the sample at Column 2 or Row 2. If they are both + -1, we would return Column 9, Row 9. +-----------------------------------------------------------------------------*/ return *terrainModP(pamP, terrain, x, y); } static void +setElev(struct pam * const pamP, + tuple ** const terrain, + int const cx, + int const cy, + unsigned int const elevation) { + + *terrainModP(pamP, terrain, cx, cy) = MIN(pamP->maxval, elevation); +} + + + +static void smallCrater(struct pam * const pamP, tuple ** const terrain, int const cx, int const cy, - double const g) { + double const radius) { /*---------------------------------------------------------------------------- Generate a crater with a special method for tiny craters. + + Center the crater at Column 'cx', Row 'cy'; wrap as necessary to get them + on the canvas. These might even be negative. -----------------------------------------------------------------------------*/ int y; unsigned int amptot; unsigned int npatch; + assert(radius < 3); + /* Set pixel to the average of its Moore neighborhood. */ for (y = cy - 1, amptot = 0, npatch = 0; y <= cy + 1; ++y) { @@ -238,12 +280,48 @@ smallCrater(struct pam * const pamP, } { unsigned int const axelev = amptot / npatch; + /* The mean elevation of the Moore neighborhood (9 pixels + centered on the crater location). + */ /* Perturb the mean elevation by a small random factor. */ - int const x = g >= 1 ? ((rand() >> 8) & 3) - 1 : 0; - *terrainModP(pamP, terrain, cx, cy) = axelev + x; + int const x = radius >= 1 ? ((rand() >> 8) & 0x3) - 1 : 0; + + assert(axelev > 0); + + setElev(pamP, terrain, cx, cy, axelev + x); + } +} + + + +static unsigned int +meanElev(struct pam * const pamP, + tuple ** const terrain, + int const cx, + int const cy, + double const radius) { +/*---------------------------------------------------------------------------- + The mean elevation in 'terrain', which is described by *pamP, within + 'radius' pixels vertically and horizontally of (cx, cy). + + We assume the area is a fraction the whole 'terrain'. +-----------------------------------------------------------------------------*/ + unsigned int amptot; + unsigned int npatch; + int y; + + for (y = cy - radius, amptot = 0, npatch = 0; y <= cy + radius; ++y) { + int x; + for (x = cx - radius; x <= cx + radius; ++x) { + amptot += terrainMod(pamP, terrain, x, y); + ++npatch; + } } + assert(npatch > 0); + + return amptot / npatch; } @@ -258,39 +336,24 @@ normalCrater(struct pam * const pamP, Generate a regular (not tiny) crater. Generate an impact feature of the correct size and shape. ------------------------------------------------------------------------------*/ +----------------------------------------------------------------------------*/ int const impactRadius = (int) MAX(2, (radius / 3)); int const craterRadius = (int) radius; double const rollmin = 0.9; int y; - unsigned int amptot, axelev; - unsigned int npatch; - /* Determine mean elevation around the impact area. - We assume the impact area is a fraction of the total crater size. */ - - for (y = cy - impactRadius, amptot = 0, npatch = 0; - y <= cy + impactRadius; - ++y) { - int x; - for (x = cx - impactRadius; x <= cx + impactRadius; ++x) { - amptot += terrainMod(pamP, terrain, x, y); - ++npatch; - } - } - assert(npatch > 0); - axelev = amptot / npatch; + unsigned int const axelev = meanElev(pamP, terrain, cx, cy, impactRadius); + /* The mean elevation of the impact area, before impact */ for (y = cy - craterRadius; y <= cy + craterRadius; ++y) { - int const dysq = (cy - y) * (cy - y); + int const dysq = SQR(cy - y); int x; for (x = cx - craterRadius; x <= cx + craterRadius; ++x) { - int const dxsq = (cx - x) * (cx - x); - double const cd = (dxsq + dysq) / - (double) (craterRadius * craterRadius); + int const dxsq = SQR(cx - x); + double const cd = (dxsq + dysq) / (double) SQR(craterRadius); double const cd2 = cd * 2.25; double const tcz = sqrt(DepthBias2) - sqrt(fabs(1 - cd2)); double cz; @@ -312,7 +375,7 @@ normalCrater(struct pam * const pamP, (terrainMod(pamP, terrain, x, y) + cz) * roll; av = MAX(1000, MIN(64000, av)); - *terrainModP(pamP, terrain, x, y) = av; + setElev(pamP, terrain, x, y, av); } } } @@ -329,7 +392,12 @@ plopCrater(struct pam * const pamP, tuple ** const terrain, int const cx, int const cy, - double const radius) { + double const radius, + bool const verbose) { + + if (verbose && pm_have_float_format()) + pm_message("Plopping crater at (%4d, %4d) with radius %g", + cx, cy, radius); if (radius < 3) smallCrater (pamP, terrain, cx, cy, radius); @@ -340,40 +408,58 @@ plopCrater(struct pam * const pamP, static void +initCanvas(unsigned int const width, + unsigned int const height, + struct pam * const pamP, + tuple *** const terrainP) { +/*---------------------------------------------------------------------------- + Initialize the output image to a flat area of middle elevation. +-----------------------------------------------------------------------------*/ + tuple ** terrain; /* elevation array */ + unsigned int row; + + pamP->size = sizeof(*pamP); + pamP->len = PAM_STRUCT_SIZE(tuple_type); + pamP->file = stdout; + pamP->format = PAM_FORMAT; + pamP->height = height; + pamP->width = width; + pamP->depth = 1; + pamP->maxval = 65535; + pamP->bytes_per_sample = 2; + STRSCPY(pamP->tuple_type, "elevation"); + + terrain = pnm_allocpamarray(pamP); + + for (row = 0; row < pamP->height; ++row) { + unsigned int col; + for (col = 0; col < pamP->width; ++col) + terrain[row][col][0] = pamP->maxval / 2; + } + *terrainP = terrain; +} + + + +static void genCraters(struct CmdlineInfo const cmdline) { /*---------------------------------------------------------------------------- Generate cratered terrain -----------------------------------------------------------------------------*/ tuple ** terrain; /* elevation array */ - unsigned int row; struct pam pam; /* Allocate the elevation array and initialize it to mean surface elevation. */ - pam.size = sizeof(pam); - pam.len = PAM_STRUCT_SIZE(tuple_type); - pam.file = stdout; - pam.format = PAM_FORMAT; - pam.height = cmdline.height; - pam.width = cmdline.width; - pam.depth = 1; - pam.maxval = 65535; - pam.bytes_per_sample = 2; - STRSCPY(pam.tuple_type, "elevation"); - - terrain = pnm_allocpamarray(&pam); + initCanvas(cmdline.width, cmdline.height, &pam, &terrain); - for (row = 0; row < pam.height; ++row) { - unsigned int col; - for (col = 0; col < pam.width; ++col) - terrain[row][col][0] = pam.maxval / 2; - } - if (cmdline.test) plopCrater(&pam, terrain, - pam.width/2, pam.height/2, (double) cmdline.radius); + pam.width/2 + cmdline.offset, + pam.height/2 + cmdline.offset, + (double) cmdline.radius, cmdline.verbose); else { unsigned int const ncraters = cmdline.number; /* num of craters */ unsigned int l; @@ -391,7 +477,7 @@ genCraters(struct CmdlineInfo const cmdline) { */ double const radius = sqrt(1 / (M_PI * (1 - cast(0.9999)))); - plopCrater(&pam, terrain, cx, cy, radius); + plopCrater(&pam, terrain, cx, cy, radius, cmdline.verbose); if (((l + 1) % 100000) == 0) pm_message("%u craters generated of %u (%u%% done)", |